java.lang.illegalstateexception could not find a method (view) in the activity class android fragment

android, android-gridview

Solution

You can't register the `onClick` callback(using `android:onClick`) for the `Button`(from the layout of the `Dialog`) in the `Fragment` class because Android will not find it as it will search only the `Activity` for a method matching that name(`Btn_pumpInfo_Clicked`) and it will throw that exception. Instead look for the `Button` in the `Dialog` and assign it a normal listener:

//...
dialog.setContentView(R.layout.pump_menu)
Button b = (Button) dialog.findViewById(R.id.Button_pumpInfo);
b.setOnClickListener(new OnClickListener() {

   @Override
   public void onCLick(View v) {
       // profit
   }
});

Or move the method :

public void Btn_pumpInfo_Clicked(View v) {
    // TODO Auto-generated method stub
    Toast.makeText(getActivity(), "You clicked on Item 1",
            Toast.LENGTH_LONG).show();
}

in the `Activity` class if it fits you.

Problem

In my program, I am using a gridview with some images. I want to show a menu when user tapped on an image in gridview and then select an action to do from the menu showed. Here is my code: ``` package Kazemi.Alireza.scada; import android.annotation.SuppressLint; import android.app.Dialog; import android.app.FragmentManager; import android.content.Context; import android.graphics.Typeface; import android.graphics.drawable.AnimationDrawable; import android.os.Bundle; import android.support.v4.app.Fragment; import android.view.ContextMenu; import android.view.ContextMenu.ContextMenuInfo; import android.view.Gravity; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.view.WindowManager; import android.view.ViewGroup.LayoutParams; import android.widget.AdapterView; import android.widget.AdapterView.AdapterContextMenuInfo; import android.widget.BaseAdapter; import android.widget.Button; import android.widget.GridView; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.PopupWindow; import android.widget.TextView; import android.widget.Toast; import android.widget.AdapterView.OnItemClickListener; @SuppressLint("NewApi") public class CitiesTab extends Fragment { AnimationDrawable[] frameAnimation; ImageAdapter ia; GridView gridView; int in; public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return (LinearLayout)inflater.inflate(R.layout.citytab, container, false); } public void onStart() { super.onStart(); ia = new ImageAdapter(getActivity()); gridView = (GridView) getActivity().findViewById(R.id.gridview); gridView.setAdapter(ia); gridView.post(new Starter()); gridView.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView<?> parent, View v, int position, long id) { dialog = new Dialog(getActivity(), android.R.style.Theme_InputMethod); dialog.setContentView(R.layout.pump_menu); }}); /*Button btn = (Button) getActivity().findViewById(R.id.Button_pumpInfo); btn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Toast.makeText(getActivity(), "You clicked on Item 1", Toast.LENGTH_LONG).show(); } });*/ } public void Btn_pumpInfo_Clicked(View v) { // TODO Auto-generated method stub Toast.makeText(getActivity(), "You clicked on Item 1", Toast.LENGTH_LONG).show(); } ``` } here is my pump_menu.xml code: ``` <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="#a5c5f0" android:orientation="vertical" > <Button android:id="@+id/Button_pumpInfo" android:layout_height="40dp" android:text="@string/menu_pumpinfo_item1" android:textSize="11sp" android:layout_width="125dp" android:background="#a5c5f0" android:onClick="Btn_pumpInfo_Clicked"/> ``` and citytab.xml : ``` <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <GridView android:id="@+id/gridview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:numColumns="auto_fit" android:verticalSpacing="10dp" android:horizontalSpacing="10dp" android:columnWidth="90dp" android:stretchMode="columnWidth" android:gravity="center" /> <ImageView android:id="@+id/gifViewer" android:layout_width="wrap_content" android:layout_height="wrap_content" android:scaleType="center"/> </LinearLayout> ``` When I use this code an error occured: ``` java.lang.RuntimeException: Unable to start activity ComponentInfo{Kazemi.Alireza.scada/Kazemi.Alireza.scada.MainMenu}: java.lang.NullPointerException ``` And when i comment the Btn_pumpInfo_Clicked() method and uncomment the button listener in onStart() the following error occurs: ``` java.lang.IllegalStateException: Could not find a method Btn_pumpInfo_Clicked(View) in the activity class android.view.ContextThemeWrapper for onClick handler on view class android.widget.Button with id 'Button_pumpInfo' ``` Where is the problem?

Original source